Study of Erosion Control Practices on Mine Waste Dumps at Limestone Sites in Benue State, North Central Nigeria

Erosion of mine waste dumps at limestone quarry sites in Benue State, North Central Nigeria, contributes to sedimentation of waterways, loss of topsoil, and slope instability. This study examines the effectiveness of erosion control practices on waste rock dumps at five limestone mining sites in the Gboko and Yandev areas of Benue State. Field assessments were conducted to characterise dump geometry, material type, and surface drainage conditions. Universal Soil Loss Equation parameters were estimated for each dump surface, and erosion rates were calculated under current conditions. Erosion control measures present at each site, including rock check dams, gabion structures, and revegetation attempts, were audited for design adequacy and maintenance status. Results indicate that erosion rates on unvegetated dump slopes exceed 50 tonnes per hectare per year under the rainfall intensities typical of the Benue region. Sites with established grass cover on dump slopes show significantly reduced erosion rates averaging 8 tonnes per hectare per year. However, grass establishment is constrained by the alkaline and low-organic-matter character of limestone waste material. Recommendations include the application of organic soil amendments prior to seeding, installation of terracing on steep dump slopes, and mandatory erosion control plans as conditions of mining licences. Keywords: erosion control, mine waste dumps, limestone mining, Benue State, revegetation.